The Mechanism of Employing the Theoretical Approach in Scientific Research

In the field of sociology, researchers require a theoretical approach when conducting scientific research due to its significant importance in laying the foundation for understanding the studied phenomenon. Many students and researchers inquire about the most suitable approach that contributes to providing the research with a conceptual model and intellectual and ideological frameworks. These frameworks support the researcher in the process of analysis and interpretation of the research topic, aiming to achieve logical sequence and methodological coherence throughout each stage of the research. Consequently, this article aims to explore the theoretical approach and its application in scientific research in the social sciences, relying on the following elements: 1) Concepts and meanings; 2) The relationship between theory and scientific research; 3) Why we need a theoretical approach in scientific research?; 4) Employing the theoretical approach in scientific research; 5) How to formulate the theoretical approach in the theoretical aspect

The role of Ministry of agriculture, forestry and water management in olive growing development

U članku se iznosi pregled stanja maslinarstva u Hrvatskoj i mjera što ih poduzima Ministarstvo poljoprivrede šumarstva i vodnoga gospodarstva.The situation in olive growing in Croatia and the measures taken by the Ministry of Agriculture, Forestry and Water Management are given in the article

Elektronsko mikroskopijsko proučavanje uređenja ravnina–“lanaca” kod visokotemperaturnih supravodiča tipa YBCO

Structures of a number of high-Tc superconducting cuprates related to the prototype YBCO compound, were studied by means of high resolution electron microscopy (HREM) and electron diffraction (ED). Commensurate superstructures or incommensurate modulated structures were induced by various metal atom substitutions for Cu in the \u27\u27chain\u27\u27-layer and its ordering. Metal (M) and oxygen (O) atom ordering is confined mainly in the MO1-x-"chain\u27\u27 layers, while the remaining part of the crystal structure, as well as the material\u27s superconducting features, are hardly affected.Strukture nekih supravodljivih kuprata, sličnih osnovnom spoju YBCO s visokim Tc, proučavane su tehnikom visoko-razlučujuće elektronske mikroskopije i elektronske difrakcije. Nađeno je da zamjena atoma bakra u ravninama “lanaca” raznim metalnim atomima uzrokuje njihovo uređenje i pojavu sumjerljivih nadstruktura ili nesumjerljivo moduliranih struktura. Odgovarajuće uređenje metalnih (M) i kisikovih (O) atoma ograničeno je na MO1−x ravnine “lanaca” bez većeg utjecaja kako na ostali dio strukture, tako i na osnovna supravodljiva svojstva

Elektronsko mikroskopijsko proučavanje uređenja ravnina–“lanaca” kod visokotemperaturnih supravodiča tipa YBCO

Structures of a number of high-Tc superconducting cuprates related to the prototype YBCO compound, were studied by means of high resolution electron microscopy (HREM) and electron diffraction (ED). Commensurate superstructures or incommensurate modulated structures were induced by various metal atom substitutions for Cu in the \u27\u27chain\u27\u27-layer and its ordering. Metal (M) and oxygen (O) atom ordering is confined mainly in the MO1-x-"chain\u27\u27 layers, while the remaining part of the crystal structure, as well as the material\u27s superconducting features, are hardly affected.Strukture nekih supravodljivih kuprata, sličnih osnovnom spoju YBCO s visokim Tc, proučavane su tehnikom visoko-razlučujuće elektronske mikroskopije i elektronske difrakcije. Nađeno je da zamjena atoma bakra u ravninama “lanaca” raznim metalnim atomima uzrokuje njihovo uređenje i pojavu sumjerljivih nadstruktura ili nesumjerljivo moduliranih struktura. Odgovarajuće uređenje metalnih (M) i kisikovih (O) atoma ograničeno je na MO1−x ravnine “lanaca” bez većeg utjecaja kako na ostali dio strukture, tako i na osnovna supravodljiva svojstva

Uređenje (Ba/Sr)O-dvoslojeva u supravodljivom kupratu RE2(Ba/Sr)2GaCu2O9

Ordering in the (Ba/Sr/Nd)O bi-layers (of "Rock-Salt" type structure) of the RE2(Ba0.65Sr0.20Nd0.15)2GaCu2O9 high-Tc superconducting cuprate was investigated by electron microscopy and diffraction. Besides the average layered structure based on the tetragonal perovskite cell ap×ap×cp and the meandering chain superstructure based on the orthorhombic 4ap×2ap×cp cell in the GaO-layers, an additional ordering was found in the pairs of (Ba/Sr/Nd)O-...-(Ba/Sr/Nd)O layers. We propose a model for ordering of 3Ba and 1Sr cations on a two-dimensional 2ap×2ap lattice cell in each (Ba/Sr/Nd)O layer. This compositional intra-layer ordering is accompanied by the inter-layer plane stacking disorder. The 4-fold symmetry of the average tetragonal structure is preserved, while the translation parameters in the (a,b) plane are doubled. This local ordering in the RS-type bi-layers hardly affects the symmetry of the basic structure; however, it may act as a source of weak anisotropy in the CuO2-layers.Strukturno uređenje (Ba/Sr/Nd)O dvoslojeva u supravodljivom kupratu sastava RE2(Ba/Sr)2GaCu2O9 istraživano je pomoću elektronske mikroskopije i difrakcije. Osim prosječne tetragonske strukture na osnovi slojevite perovskitske tetragonske ćelije ap i ap i cp, i nadstrukture meandrirajućih lanaca u GaO-ravninama s ortorombskom ćelijom 4ap i 2ap i cp, nad–eno je dodatno uređenje u parovima (Ba/Sr/Nd)O-...-(Ba/Sr/Nd)O ravnina. Predložen je model uređenja 3Ba i 1Sr kationa unutar 2ap i 2ap dvodimenzijske ćelije u svakoj (Ba/Sr/Nd)O ravnini. Ovo unutar-ravninsko uređenje popraćeno je među-ravninskim neredom u nizu slaganja slojeva. Simetrija 4-reda, koja je svojstvena prosječnoj tetragonskoj strukturi ostaje sačuvana, uz podvostručenje parametara rešetke u j a k bl ravnini. Opaženo uređenje unutar (Ba/Sr/Nd)O dvoslojeva ovog supravodljivog kuprata nema jaki utjecaj na simetriju osnovne strukture, ali može biti izvor lokalne anizotropije u CuO2-ravninama

Uređenje (Ba/Sr)O-dvoslojeva u supravodljivom kupratu RE2(Ba/Sr)2GaCu2O9

Ordering in the (Ba/Sr/Nd)O bi-layers (of "Rock-Salt" type structure) of the RE2(Ba0.65Sr0.20Nd0.15)2GaCu2O9 high-Tc superconducting cuprate was investigated by electron microscopy and diffraction. Besides the average layered structure based on the tetragonal perovskite cell ap×ap×cp and the meandering chain superstructure based on the orthorhombic 4ap×2ap×cp cell in the GaO-layers, an additional ordering was found in the pairs of (Ba/Sr/Nd)O-...-(Ba/Sr/Nd)O layers. We propose a model for ordering of 3Ba and 1Sr cations on a two-dimensional 2ap×2ap lattice cell in each (Ba/Sr/Nd)O layer. This compositional intra-layer ordering is accompanied by the inter-layer plane stacking disorder. The 4-fold symmetry of the average tetragonal structure is preserved, while the translation parameters in the (a,b) plane are doubled. This local ordering in the RS-type bi-layers hardly affects the symmetry of the basic structure; however, it may act as a source of weak anisotropy in the CuO2-layers.Strukturno uređenje (Ba/Sr/Nd)O dvoslojeva u supravodljivom kupratu sastava RE2(Ba/Sr)2GaCu2O9 istraživano je pomoću elektronske mikroskopije i difrakcije. Osim prosječne tetragonske strukture na osnovi slojevite perovskitske tetragonske ćelije ap i ap i cp, i nadstrukture meandrirajućih lanaca u GaO-ravninama s ortorombskom ćelijom 4ap i 2ap i cp, nad–eno je dodatno uređenje u parovima (Ba/Sr/Nd)O-...-(Ba/Sr/Nd)O ravnina. Predložen je model uređenja 3Ba i 1Sr kationa unutar 2ap i 2ap dvodimenzijske ćelije u svakoj (Ba/Sr/Nd)O ravnini. Ovo unutar-ravninsko uređenje popraćeno je među-ravninskim neredom u nizu slaganja slojeva. Simetrija 4-reda, koja je svojstvena prosječnoj tetragonskoj strukturi ostaje sačuvana, uz podvostručenje parametara rešetke u j a k bl ravnini. Opaženo uređenje unutar (Ba/Sr/Nd)O dvoslojeva ovog supravodljivog kuprata nema jaki utjecaj na simetriju osnovne strukture, ali može biti izvor lokalne anizotropije u CuO2-ravninama

Quasiparticle Dynamics in the Kondo Lattice Model at Half Filling

We study spectral properties of quasiparticles in the Kondo lattice model in one and two dimensions including the coherent quasiparticle dispersions, their spectral weights and the full two-quasiparticle spectrum using a cluster expansion scheme. We investigate the evolution of the quasiparticle band as antiferromagnetic correlations are enhanced towards the RKKY limit of the model. In both the 1D and the 2D model we find that a repulsive interaction between quasiparticles results in a distinct antibound state above the two-quasiparticle continuum. The repulsive interaction is correlated with the emerging antiferromagnetic correlations and can therefore be associated with spin fluctuations. On the square lattice, the antibound state has an extended s-wave symmetry.Comment: 8 pages, 11 figure

Magnetic anisotropy of spin tetramer system SeCuO3_3 studied by torque magnetometry and ESR spectroscopy

We present an experimental study of macroscopic and microscopic magnetic anisotropy of a spin tetramer system SeCuO$_3$ using torque magnetometry and ESR spectroscopy. Large rotation of macroscopic magnetic axes with temperature observed from torque magnetometry agrees reasonably well with the rotation of the $\textbf{g}$ tensor above $T \gtrsim 50$~K. Below 50~K, the $\textbf{g}$ tensor is temperature independent, while macroscopic magnetic axes continue to rotate. Additionally, the susceptibility anisotropy has a temperature dependence which cannot be reconciled with the isotropic Heisenberg model of interactions between spins. ESR linewidth analysis shows that anisotropic exchange interaction must be present in SeCuO$_3$. These findings strongly support the presence of anisotropic exchange interactions in the Hamiltonian of the studied system. Below $T_N=8$~K, the system enters a long - range antiferromagnetically ordered state with easy axis along the $^*$ direction. Small but significant rotation of magnetic axes is also observed in the antiferromagnetically ordered state suggesting strong spin-lattice coupling in this system.Comment: 14 pages, 13 figure